WCDMA Radio Interface Physical Layer.pdf

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WCDMA Radio Interface Physical Layer ISSUE 1.0

HUAWEI TECHNOLOGIES CO., LTD.

www.huawei.com

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The physical layer offers data transport services to higher layers. The access to these services is through the use of transport channels via the MAC sub-layer. The physical layer is expected to perform the following functions in order to provide the data transport service, for example Modulation and spreading/demodulation and despreading, Inner loop power control etc.


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References TS 25.104 UTRA (BS) FDD Radio Transmission and Reception TS 25.201 Physical layer-general description TS 25.211 Physical channels and mapping of transport channels onto physical channels (FDD) TS 25.212 Multiplexing and channel coding (FDD) TS 25.213 Spreading and modulation (FDD) TS 25.214 Physical layer procedures (FDD) TS 25.308 UTRA High Speed Downlink Packet Access (HSDPA); Overall description; Stage 2 TR 25.877 High Speed Downlink Packet Acces (HSDPA) Iub/Iur Protocol Aspects TR 25.858 Physical layer aspects of UTRA High Speed Downlink Packet Access


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Upon completion of this course, you will be able to: Outline radio interface protocol Architecture Describe key technology of UMTS physical layer Describe UMTS physical layer procedures


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Chapter 1 Physical Layer Overview Chapter 2 Physical Layer Key Technology Chapter 3 Physical Layer Processing Procedure Chapter 4 Physical Layer Procedures


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UTRAN Protocol Structure Core Network Iu

Iu RNS

RNS Iur

RNC Iub NodeB

Iub

Iub NodeB

NodeB


RNC

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Iub NodeB

Radio Interface Protocol Structure GC

Nt

DC

Duplication avoidance Nt

GC

DC

C-plane signaling

U-plane information control

L3 Radio Bearers

control control

control

control

RRC

UuS boundary

PDCP

RLC

RLC

RLC

PDCP

RLC RLC

RLC

L2/PDCP

RLC

BMC

L2/BMC

RLC

L2/RLC

Logical Channels


MAC

L2/MAC

PHY

Transport Channels L1

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Nt

DC


GC

DC

C-plane signaling


L3 Radio Bearers

control control

control

control

RRC

UuS boundary

PDCP

RLC

RLC

RLC

PDCP

RLC RLC

RLC

L2/PDCP

RLC

BMC

L2/BMC

RLC

L2/RLC

Logical Channels


MAC

L2/MAC

PHY


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Nt

DC


GC

DC

C-plane signaling


L3 Radio Bearers

control control

control

control

RRC

UuS boundary

PDCP

RLC

RLC

RLC

PDCP

RLC RLC

RLC

L2/PDCP

RLC

BMC

L2/BMC

RLC

L2/RLC

Logical Channels


MAC

L2/MAC

PHY


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Nt

DC


GC

DC

C-plane signaling


L3 Radio Bearers

control control

control

control

RRC

UuS boundary

PDCP

RLC

RLC

RLC

PDCP

RLC RLC

RLC

L2/PDCP

RLC

BMC

L2/BMC

RLC

L2/RLC

Logical Channels


MAC

L2/MAC

PHY


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Spreading Technology Spreading consists of 2 steps： Channelization operation, which transforms data symbols into chips. Thus increasing the bandwidth of the signal, The number of chips per data symbol is called the Spreading Factor（SF）.The operation is done by multiplying with OVSF code. Scrambling operation is applied to the spreading signal .

Chips after spreading

Data bit

OVSF code


Scrambling code

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Channelization Code OVSF code is used as channelization code The channelization codes are uniquely described as Cch,SF,k, where SF is the spreading factor of the code and k is the code number, 0

k

C ch,4,0 =(1,1,1,1) C ch,2,0 = (1,1) C ch,4,1 = (1,1,-1,-1) C ch,1,0 = (1) C ch,4,2 = (1,-1,1,-1) C ch,2,1 = (1,-1) C ch,4,3 = (1,-1,-1,1) SF = 1

SF = 2


SF = 4 All rights reserved

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SF-1.

Scrambling Code Scrambling code: GOLD sequence. Scrambling code period: 10ms ,or 38400 chips. The code used for scrambling of the uplink DPCCH/DPDCH may be of either long or short type, There are 224 long and 224 short uplink scrambling codes. Uplink scrambling codes are assigned by higher layers. For downlink physical channels, a total of 218-1 = 262,143 scrambling codes can be generated. scrambling codes k = 0, 1, …, 8191 are used.


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Primary Scrambling Code Primary scrambling code 0 Secondary scrambling code 1

Set 1

……

…

Secondary scrambling code 15

Set 511

……

Scrambling codes for downlink physical channels

Set 0

Primary scrambling code 511× ×16

…… 8192 scrambling codes

512 sets

Secondary scrambling code 511× ×16＋＋15

A primary scrambling code and 15 secondary scrambling codes are included in a set. HUAWEI TECHNOLOGIES CO., LTD.

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Primary Scrambling Code Group Primary scrambling code 0 Primary scrambling code 1

Group 1

……

…

Primary scrambling code 15

Group 63

……

Primary scrambling codes for downlink physical channels

Group 0

Primary scrambling code 8*63

…… Primary scrambling code 63*8＋＋7 512 primary scrambling codes

64 primary scrambling code groups


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Each group consists of 8 primary scrambling codes

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Chapter 2 Physical Layer Key Technology Section 1 Physical Channel Structure and Functions Section 2 Channel Mapping


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WCDMA radio interface has three kinds of channels In terms of protocol layer, the WCDMA radio interface has three channels: Physical channel, transport channel and logical channel. Logical channel: Carrying user services directly. According to the types of the carried services, it is divided into two types: Control channel and service channel. Transport channel: It is the interface of radio interface layer 2 and physical layer, and is the service provided for MAC layer by the physical layer. According to whether the information transported is dedicated information for a user or common information for all users, it is divided into dedicated channel and common channel. Physical channel: It is the ultimate embodiment of all kinds of information when they are transmitted on radio interfaces. Each kind of channel which uses dedicated carrier frequency, code (spreading code and scramble) and carrier phase (I or Q) can be regarded as a dedicated channel. HUAWEI TECHNOLOGIES CO., LTD.

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Logical Channel Dedicated traffic channel

(DTCH)

Common traffic channel

(CTCH)

Broadcast control channel

(BCCH)

Paging control channel

(PCCH)

Dedicate control channel

(DCCH)

Common control channel

(CCCH)


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Traffic channel

Control channel

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Transport Channel Dedicated Channel

(DCH)

-DCH is an uplink or downlink channel

Broadcast channel

(BCH)

Forward access channel

(FACH)

Paging channel

(PCH)

Random access channel

(RACH)

Dedicated transport channel

Common transport channel

High-speed downlink shared channel (HS-DSCH)


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Physical Channel A physical channel is defined by a specific carrier frequency, code (scrambling code, spreading code) and relative phase. In UMTS system, the different code (scrambling code or spreading code) can distinguish the channels. Most channels consist of radio frames and time slots, and each radio frame consists of 15 time slots. Two types of physical channel:UL and DL Physical Channel

Frequency, Code, Phase


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Downlink Physical Channel Downlink Dedicated Physical Channel

(Downlink DPCH) Downlink Common Physical Channel

Common Control Physical Channel (CCPCH) Synchronization Channel

(SCH)

Paging Indicator Channel

(PICH)

Acquisition Indicator Channel

(AICH)

Downlink Physical Channel

Common Pilot Channel (CPICH) High-Speed Packet Downlink Shared Channel (HS-PDSCH) High-Speed Shared Control Channel (HSSCCH) HUAWEI TECHNOLOGIES CO., LTD.

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Uplink Physical Channel Uplink Dedicated Physical Channel Uplink Dedicated Physical Data Channel (Uplink DPDCH) Uplink Dedicated Physical Control Channel (Uplink DPCCH) High-Speed Dedicated Physical Channel (HS-DPCCH)

Uplink Physical Channel

Uplink Common Physical Channel Physical Random Access Channel (PRACH)


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Function of physical channel Cell broadcast channels P-CPICH-Primary P-CPICH-Primary Common Common Pilot Pilot Channel Channel S-CPICH-Secondary S-CPICH-Secondary Common Common Pilot Pilot Channel Channel P-CCPCH-Primary P-CCPCH-Primary Common Common Control Control Physical Physical Channel Channel SCHSynchronisation Channel SCH- Synchronisation Channel

Paging channels S-CCPCH-Secondary S-CCPCH-Secondary Common Common Control Control Physical Physical Channel Channel PICH-Paging PICH-Paging Indicator Indicator Channel Channel

Random access channels Node B

PRACH-Physical PRACH-Physical Random Random Access Access Channel Channel

UE

AICH-Acquisition AICH-Acquisition Indicator Indicator Channel Channel

Dedicated channels DPDCH-Dedicated DPDCH-Dedicated Physical Physical Data Data Channel Channel DPCCH-Dedicated DPCCH-Dedicated Physical Physical Control Control Channel Channel

High speed downlink share channels HS-SCCH-High HS-SCCH-High Speed Speed Share Share Control Control Channel Channel HS-PDSCH-High HS-PDSCH-High Speed Speed Physical Physical Downlink Downlink Share Share Channel Channel HS-DPCCH-High HS-DPCCH-High Speed Speed Dedicated Dedicated Physical Physical Control Control Channel Channel


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Primary Synchronization Channel (P-SCH) Used for cell search Two sub channels: P-SCH and S-SCH. SCH is transmitted at the first 256 chips of every time slot. PSC is transmitted repeatedly in each time slot. Slot #0

Primary SCH Secondary SCH

SSC specifies the scrambling code groups of the cell. SSC is chosen from a set of 16 different codes of length 256, there are altogether 64 primary scrambling code groups.

Slot #1

ac p

ac p

ac si,0

ac si,1

Slot #14

ac p acsi,14

256 chips 2560 chips One 10 ms SCH radio frame


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Secondary Synchronization Channel (S-SCH) Scrambling Code Group Group 0 Group 1 Group 2 Group 3 Group 4 … Group 61 Group 62 Group 63

#0

#1

#2

#3

#4

#5

slot number #6 #7 #8

1 1 1 1 1

1 1 2 2 2

2 5 1 3 16

8 16 15 1 6

9 7 5 8 6

10 3 5 6 11

15 14 12 5 15

8 16 16 2 5

10 3 6 5 12

16 10 11 8 1

2 5 2 4 15

7 12 16 4 12

15 14 11 6 16

7 12 15 3 11

16 10 12 7 2

9 9 9

10 11 12

13 12 10

10 15 15

11 12 13

15 9 14

15 13 9

9 13 14

16 11 15

12 14 11

14 10 11

13 16 13

16 15 12

14 14 16

11 16 10

Slot # ?

Slot #?

Slot #?

P-SCH

acp

acp

acp

S-SCH

16

6

11

#9

#10 #11 #12 #13 #14

……..

Group 2 Slot 7, 8, 9

256 chips 2560 chips


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Common Pilot Channel(CPICH) Common Pilot Channel (CPICH) Carries pre-defined sequence. Fixed rate 30Kbps， SF=256 Primary CPICH Uses the fixed channel code -- Cch,256,0 Scrambled by the primary scrambling code Only one CPICH per cell Broadcast over the entire cell The P-CPICH is a phase reference for SCH, Primary CCPCH, AICH, PICH. By default, it is also a phase reference for downlink DPCH. Pre-defined symbol sequence Tslot = 2560 chips , 20 bits

Slot #0

Slot # i

Slot #1

Slot #14

1 radio frame: Tr = 10 ms


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Primary Common Control Physical Channel (PCCPCH) Fixed rate, fixed OVSF code（30kbps，Cch,256,1） Carry BCH transport channel The PCCPCH is not transmitted during the first 256 chips of each time slot. Only data part STTD transmit diversity may be used 256 chips PCCPCH Data

SCH

18 bits T

Slot #0

Slot #1

slot

= 2560 chips,20 bits

Slot #i

Slot #14

1 radio frame: T f = 10 ms


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Paging Indicator Channel (PICH) PICH is a fixed-rate (SF=256) physical channel used to carry the Paging Indicators (PI). Frame structure of PICH: one frame of length 10ms consists of 300 bits of which 288 bits are used to carry paging indicators and the remaining 12 bits are not defined. N paging indicators {PI0, …, PIN-1} in each PICH frame, N=18, 36, 72, or 144. If a paging indicator in a certain frame is set to 1, it indicates that UEs associated with this paging indicator should read the corresponding frame of the associated S-CCPCH.

288 bits for paging indication b0 b1

12 bits (undefined) b 287 b 288

One radio frame (10 ms)


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b 299

Secondary Common Control Physical Channel (SCCPCH) Carry FACH and PCH.

SF =256 - 4.

Two kinds of SCCPCH: with or without TFCI. UTRAN decides if a TFCI should be transmitted, UE must support TFCI.

FACH and PCH can be mapped to the same or separate SCCPCHs. If

Possible rates are the same as that of downlink DPCH

can be mapped to the same fame.

Data

TFCI N TFCI bits

Pilot N Pilot bits

N Data bits T slot = 2560 chips,

Slot #0

mapped to the same S-CCPCH, they

Slot #1

20*2 k bits (k=0..6)

Slot #i

Slot #14

1 radio frame: T f = 10 ms


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Physical Random Access Channel (PRACH) The random-access transmission data consists of two parts: One or several preambles：each preamble is of length 4096chips and consists of 256 repetitions of a signature whose length is 16 chips，16 available signatures totally 10 or 20ms message part Which signature is available and the length of message part are determined by higher layer

Preamble

Preamble

Preamble

4096 chips

Preamble

Message part 10 ms (one radio frame)

Preamble

Preamble

4096 chips


Message part 20 ms (two radio frames)

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PRACH Access Timeslot Structure radio frame: 10 ms

radio frame: 10 ms

5120 chips #1 Access slot #0 Access slot #1

#2

#3

#4

#5

#6

#7

#8

#9

#10

#11

#12

#13

#14

Random Access Transmission Random Access Transmission

Access slot #7

Random Access Transmission

Access slot #8

Random Access Transmission

Access slot #14


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PRACH Message Structure Data N data bits

Data

Pilot N Pilot bits

Control

TFCI N TFCI bits

T slot = 2560 chips, 10*2 k bits (k=0..3)

Slot # 0

Slot # 1

Slot # i

Slot # 14

Message part radio frame TRACH = 10 ms


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Acquisition Indicator Channel (AICH) Frame structure of AICH：two frames, 20 ms ，consists of a repeated sequence of 15 consecutive AS, each of length 20 symbols(5120 chips). Each time slot consists of two parts，an Acquisition-Indicator(AI) and a part of duration 1024chips with no transmission. Acquisition-Indicator AI have 16 kinds of Signature. CPICH is the phase reference of AICH. AI part a0 a1 a2

AS #14

AS #0

AS #1

Unused part a30 a31 a32 a33

a38 a39

AS #i

AS #14

20 ms


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AS #0

Uplink Dedicated Physical Channel (DPDCH&DPCCH) DPDCH and DPCCH are I/Q code multiplexed within each radio frame DPDCH carries data generated at Layer 2 and higher layer DPCCH carries control information generated at Layer 1 Each frame is 10ms and consists of 15 time slots, each time slot consists of 2560 chips The spreading factor of DPDCH is from 4 to 256 The spreading factor of DPDCH and DPCCH can be different in the same Layer 1 connection Each DPCCH time slot consists of Pilot, TFCI，FBI，TPC


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Frame Structure of Uplink DPDCH/DPCCH

Data N databits

DPDCH

DPCCH

Pilot Npilot bits

TFCI NTFCI bits

FBI NFBI bits

TPC NTPC bits

Tslot = 2560 chips, 10 k *2 bits (k=0..6)

Slot #0 Slot #1

Slot #i

Slot #14

1 radio frame: Tf = 10 ms


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Downlink Dedicated Physical Channel (DPDCH+DPCCH) DCH consists of dedicated data and control information. Control information includes：Pilot、TPC、TFCI(optional). The spreading factor of DCH can be from 512 to 4,and can be changed during connection DPDCH and DPCCH is time multiplexed.


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Frame Structure of Downlink DPCH

DPCCH

DPDCH Data1 Ndata1 bits

TPC NTPC bits

TFCI NTFCI bits

DPDCH

DPCCH

Data2 Ndata2 bits

Pilot Npilot bits

Tslot = 2560 chips, 10*2 k bits (k=0..7)

Slot #0

Slot #1

Slot #i

Slot #14

One radio frame, Tf = 10 ms


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High-Speed Physical Downlink Shared Channel (HS-PDSCH) Bear service data and layer2 overhead bits mapped from the transport channel SF=16, can be configured several channels to increase data service

Data N Data 1 bits T slot = 2560 chips, M*10*2 k bits (k=4)

Slot #0

Slot#1

Slot #2

1 subframe: Tf = 2 ms


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High-Speed Shared Control Channel (HS-SCCH) Carries physical layer signalling to a single UE ,such as modulation scheme (1 bit) ,channelization code set (7 bit), transport Block size (6bit),HARQ process number (3bit), redundancy version (3bit), new data indicator (1bit), Ue identity (16bit) HS-SCCH is a fixed rate (60 kbps, SF=128) downlink physical channel used to carry downlink signalling related to HS-DSCH transmission

Data N Data 1bits T slot = 2560 chips, 40 bits

Slot #0

Slot#1

Slot #2

1 subframe: T f = 2 ms


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High-Speed Dedicated Physical Control Channel (HS-DPCCH )

HS-DPCCH carries information to acknowledge downlink transport blocks and feedback information to the system for scheduling and link adaptation of transport block CQI and ACK/NACK Physical Channel ,Uplink, SF=256,power control T

s lo t

2×T

= 2 5 6 0 c h ip s

s lo t

H A R Q -A C K

= 5 1 2 0 ch ip s CQI

O n e H S -D P C C H s u b fra m e (2 m s )

S u b fra m e # i

S u b fra m e # 0

O n e ra d io fra m e T


f

S u b fra m e # 4

= 10 ms

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Chapter 2 Physical Layer Key Technology Section 1 Physical Channel Structure and Functions Section 2 Channel Mapping


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Mapping Between Channels Logical channels

Transport channels

Physical channels

BCH

P-CCPCH

FACH

S-CCPCH

PCCH

PCH

S-CCPCH

CCCH

RACH

PRACH

FACH

S-CCPCH

FACH

S-CCPCH

DCH

DPDCH

HS-DSCH

HS-PDSCH

BCCH

CTCH DCCH, DTCH

RACH, FACH


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PRACH, S-CCPCH

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Chapter 3 Physical Layer Processing Procedure Section 1 Coding and Multiplexing Technology Section 2 Spreading Technology Section 3 Modulation Technology


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CRC of TB Error detection is provided on transport blocks through a Cyclic Redundancy Check (CRC) CRC size is informed by higher layer signal 0、8、12、16、24(optional) If no TB are input, no CRC bits should be attached. If TB are input with TB SIZE=0,CRC bits shall be also added ,but all CRC are zero


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TB Concatenation and Code Block Segmentation All transport blocks in a TTI are serially concatenated . The maximum size of the code blocks depends on whether convolutional coding or turbo coding is used for the TrCH . Convolutional code: if TBS SIZE>504,segmented to multiple code block of the same size. Turbo code:if TBS SIZE>5114, segmented to multiple code block of the same size. No coding:no segmentation If codes cannot be segmented evenly, fill in “0” bits at the beginning of the first code block. If the code block length of Turbo code<40, fill in “0” bits at the beginning to keep the code length constantly as 40


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Channel coding The following channel coding schemes can be applied to TrCHs: Convolutional coding, coding rates 1/3 and 1/2 are defined Turbo coding, The coding rate of Turbo coder is 1/3 No coding Usage of coding BCH, PCH and RACH——1/2 Convolutional coding DCH and FACH——1/2 or 1/3 Convolutional coding ,1/3 Turbo coding, no coding


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Rate Matching Rate matching means that bits on a transport channel are repeated or punctured. The number of bits on a transport channel can vary between different transmission time intervals(TTI). In the downlink the transmission is interrupted if the number of bits is lower than maximum. When the number of bits between different transmission time intervals in uplink is changed, bits are repeated or punctured to ensure that the total bit rate after TrCH multiplexing is identical to the total channel bit rate of the allocated dedicated physical channels.


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Interleaving Function: reduce the influence of fast fading. Two kinds of interleaving: 1st interleaving and 2nd interleaving The length of 1st interleaving is TTI of TrCH, 1st interleaving is a inter-frame interleaving The length of 2nd interleaving is a physical frame, 2nd interleaving is a intra-frame interleaving.


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Radio Frame Segmentation When the transmission time interval (TTI) is longer than 10 ms, the input bit sequence is segmented and mapped onto consecutive Fi radio frames. Following radio frame size equalisation in the UL the input bit sequence length is guaranteed to be an integer multiple of Fi. Following rate matching in the DL the input bit sequence length is guaranteed to be an integer multiple of Fi. Fi: Number of radio frames in the transmission time interval of TrCHi.


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Multiplexing of TrCH Every 10 ms, one radio frame from each TrCH is delivered to the TrCH multiplexing. These radio frames are serially multiplexed into a coded composite transport channel (CCTrCH) The format of CCTrCH is indicated by TFCI TrCH can have different TTI before multiplexing 2 types of CCTrCH:Common and dedicated Common CCTrCH should be multiplexed by common TrCH; Dedicated CCTrCH should be multiplexed by dedicated TrCH There is only one CCTrCH in uplink and one or several CCTrCH in downlink for one user


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Insertion of Discontinuous Transmission (DTX) Indication Bits In the downlink, DTX is used to fill up the radio frame with bits. DTX indication bits only indicate when the transmission should be turned off, they are not transmitted. 1st insertion of DTX indication bits This step of inserting DTX indication bits is used only if the positions of the TrCHs in the radio frame are fixed 2nd insertion of DTX indication bits The DTX indication bits inserted in this step shall be placed at the end of the radio frame.


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Physical Channel Segmentation and Mapping When multiple physical channels are used, one CCTrCH radio frame can be divided into multiple physical frames –multicode transmission Each physical channel of multicode transmission must have the same SF DPCCH and DPDCH of uplink physical channel is code multiplexed. DPCCH and DPDCH of downlink physical channel is time multiplexed Uplink physical channel must be fully filled except when cpmpressed mode is used In downlink, the PhCHs do not need to be completely filled with bits that are transmitted over the air. Values correspond to DTX indicators, which are mapped to the DPCCH/DPDCH fields but are not transmitted over the air. HUAWEI TECHNOLOGIES CO., LTD.

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Transport channel multiplexing structure for downlink

data

dataCRC dataCRC CRCdata CBL CBL d CRC a t a data

TrCH-i+1

10、20、40 or 80ms

data

data

TrCH-i

0、8、16 or 24bits

dataCRC CRC CBL data

Size Z＝

CedBL Rate CedBL Coded matched data data CedBL

512－Ktail ， Conventional code 5120－Ktail ，Turbo code

Channel Coding

or

Rate matched data

DTX

or

Data Databefore after 11stst interleaved interleaving Number of Rado frame Radio frame

Radio frame

1、2、4 or 8

Radio frame

TrCH-1 TrCH-1TrCH-2 TrCH-2 DTX CCTrCHTrCH-ITrCH-I

Ph-1 data1 TPC TFCI data2 Spreading Scrambling


pilot

Ph-P

Ph-2 data1 TPC TFCI data2

10ms

pilot

Spreading Scrambling

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10ms

data1 TPC TFCI data2 Spreading Scrambling

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pilot

Example of Coding and Multiplexing Parameters for 12.2kb/s AMR speech The number of TrChs

3

Transport block size CRC

81, 103, and 60 bits 12 bits (attached only to TrCh#1)

Coding

CC, coding rate = 1/3 for TrCh#1, 2 coding rate = 1/2 for TrCh#3

TTI

20 ms

Parameters for 3.4kb/s control channel Transport block size

148 bits

Transport block set size

148 bits

CRC Coding

16 bits CC, coding rate = 1/3

TTI

40 ms


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Example of Coding and Multiplexing T ra n sp o rt b lo c k TrC h # 1 C R C atta ch m en t

TrC h # 2

81

TrC h # 3

103

60

CRC

Tail b it attac h m en t

81

12

103 Ta il

C o n v o lu tio n a l c o d in g R = 1 /3 , 1 /2

93

8

Ta il 103

R a te m atch in g

303

333

1 st in terle av in g

3 0 3 + N RM 1

3 3 3 + N RM 2

R a d io fram e se g m en tatio n

3 0 3 + N RM 1

#1a

#1b

N R F1

N R F1

60 Ta il 60

8

136

1 3 6 + N RM 3

3 3 3 + N RM 2

#2a N RF2

8

1 3 6 + N RM3

#2b N RF2

#3a

#3b

N R F3

N RF3

N R F 1 = (3 0 3 + N R M 1 )/2 N R F 2 = (3 3 3 + N R M 2 )/2 N R F 3 = (1 3 6 + N R M 3 )/2

To T rC h M u ltip le x in g


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Example of Coding and Multiplexing(3.4kbps) T ra n s p o rt b lo c k 148

C R C a tta c h m e n t

C R C 148

T rB k c o n c a tin a tio n

1 6 b its

B T rB k s ( B = 0 ,1 )

164*B

T a il b it a tta c h m e n t

T a il 164*B

C o n v o lu tio n a l c o d in g R = 1 /3

8*B

516*B

R a te m a tc h in g In s e rtio n o f in d ic a tio n *

1

st

D T X

(5 1 6 + N

in te rle a v in g

R a d io fra m e s e g m e n ta tio n #1 [ (1 2 9 + N

R M

)* B + N

4

R M

)* B

(5 1 6 + N

R M

)* B + N

D I

(5 1 6 + N

R M

)* B + N

D I

#2 D I]

/

[ (1 2 9 + N

R M

)* B + N

#3 D I]

/

[ (1 2 9 + N

4

R M

#4

)* B + N

D I]

/

[ (1 2 9 + N

4

R M

)* B + N

D I]

/

4

T o T r C h M u ltip le x in g * I n s e rtio n o f D T X in d ic a tio n is u s e d o n ly if th e p o s itio n o f th e T r C H s in th e ra d io fr a m e is f ix e d .


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Example of Coding and Multiplexing 12.2kbpsdata #1a

#2a

#1b

12.2kbpsdata

#2b

#1c

#2c

#1a

#2a

#1b

3.4kbpsdata

#2b

#1c

#2c

#1

#2

#3

#4

TrCH multiplexing #1a

#1b

#1c

#1

#2a

#2b

#2c

#2

#1a

#1b

#1c

#3

#2a

#2b

#2c

#4

2nd interleaving Physical channel mapping

30kspsDPCH

510 1 2

slot

510 15 1 2

CFN=4N

slot

510 15 1 2

CFN=4N+1

slot

510 15 1 2

CFN=4N+2

slot

15

CFN=4N+3 Pilot symbol


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Page 58

TPC



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Page 59

Uplink DPCCH/DPDCH Spreading The DPCCH is always spread by code cc = Cch,256,0 When only 1 DPDCH exists,(Cd,1 = Cch,SF,k ) k=SF/4 The code used for scrambling of the uplink DPCCH/DPDCH may be of either long or short type D P D C H

D P D C H

c

d ,1

d

c

d ,3

d

1

I

3

c D P D C H

d ,5

d

5

S

lo n g ,n

or S

s h o rt,n

I+ jQ D P D C H

D P D C H

D P D C H

c

d ,2

d

c

d ,4

d

c

d ,6

d

2

4

Q

Up to 6 DPDCH for one user

6

c

c

j c

D P C C H


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Page 60

Uplink PRACH Spreading Message part is shown in the following figure，the value of gain factors is the same with DPDCH/DPCCH

cd

d

PRACH message data part

I

PRACH message control part

Q

cc


c

Sr-msg,n I+jQ

j

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Page 61

Downlink Spreading Downlink physical channel except SCH is first serial-to-parallel converted , spread by the spreading code, and then scrambled by a complex-valued scrambling code. The beginning chip of the scrambling code is aligned with the frame boundary of P-CCPCH. Each channel have different gain factor I

Data of physical channel except SCH

S dl,n

S I+jQ

C ch,SF,m

P

Q

j


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Page 62

S

Downlink Spreading Different physical hannel come from point S

G1

G2 P-SCH GP S-SCH GS


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Page 63



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Page 64

Uplink Modulation The chip rate is 3.84Mbps In the uplink, the complex-valued chip sequence generated by the spreading process is QPSK modulated

cos( t) Complexvalued sequence after spreading

S

Split real & imag parts

Re{S}

Pulse shaping

Im{S}

Pulse shaping -sin( t)


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Page 65

Downlink Modulation The chip rate is 3.84Mbps In the downlink, the complex-valued chip sequence generated by the spreading process is QPSK modulated

cos( t)

Complexvalued sequence after spreading

S

Split real & imag parts

Re{S}

Pulse shaping

Im{S}

Pulse shaping -sin( t)


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Page 66



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Page 67

Synchronization Procedure—Cell Search UE uses PSC to acquire slot synchronization to a cell

Slot synchronization

UE uses SSC to find frame synchronization and identify the code group of the cell found in the first step

Frame synchronization and code-group identification

UE determines the primary scrambling code through correlation over the CPICH with all codes within the identified group, and then detects the P-CCPCH and reads BCH information

Scrambling-code identification


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Page 68

Synchronization Procedure— Channel Timing Relationship Primary SCH Secondary SCH Any CPICH P -CCPCH, (SFN modulo 2) = 0

P -CCPCH, (SFN modulo 2) = 1

S-CCPCH,k

k:th S - CCPCH

PICH PICH for k:th S AICH access slo ts

#0

#1

#2

#3

DPCH,n

#4

-CCPCH

#5

#6

#7

#8

#9

#10

n:th DPCH

10 ms


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Page 69

#11

#12

#13

#14

Random access procedure

START

Choose a RACH sub channel from available ones

Get available signatures

Set Preamble Retrans Max

Set Preamble _Initial _ Power

No AI

Choose a access slot again

Send a preamble

Check the corresponding AI Get positive AI

Choose a signature and increase preamble transmit power The counter of preamble retransmit Subtract-1, Commanded preamble power increased by Power Ramp Step

Get negative AI

Increase message part power by p -m based on preamble power

Send the corresponding message part

Y Counter> 0 & Preamble powermaximum allowed power<6 dB N Set physical status to be Nack on AICH received


Set physical status to be RACH message transmitted

Set physical status to be Nack on AICH received

Report the physical status to MAC

END

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Page 70

Random Access Procedure—RACH Physical random access procedure 1. Derive the available uplink access slots, in the next full access slot set, for the set of available RACH sub-channels within the given ASC. Randomly select one access slot among the ones previously determined. If there is no access slot available in the selected set, randomly select one uplink access slot corresponding to the set of available RACH sub-channels within the given ASC from the next access slot set. The random function shall be such that each of the allowed selections is chosen with equal probability ； 2. Randomly select a signature from the set of available signatures within the given ASC. ； 3. Set the Preamble Retransmission Counter to Preamble_ Retrans_ Max HUAWEI TECHNOLOGIES CO., LTD.

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Page 71

Random Access Procedure—RACH 4. Set the parameter Commanded Preamble Power to Preamble_Initial_Power 5. Transmit a preamble using the selected uplink access slot, signature, and preamble transmission power. 6. If no positive or negative acquisition indicator (AI +1 nor –1) corresponding to the selected signature is detected in the downlink access slot corresponding to the selected uplink access slot: T A: Select the next available access slot in the set of available RACH sub-channels within the given ASC; T B: select a signature; T C: Increase the Commanded Preamble Power; T D: Decrease the Preamble Retransmission Counter by one. If the Preamble Retransmission Counter > 0 then repeat from step 6. Otherwise exit the physical random access procedure.


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Page 72

Random Access Procedure—RACH 7. If a negative acquisition indicator corresponding to the selected signature is detected in the downlink access slot corresponding to the selected uplink access slot, exit the physical random access procedure Signature 8. If a positive acquisition indicator corresponding to the selected signature is detected , Transmit the random access message three or four uplink access slots after the uplink access slot of the last transmitted preamble 9. exit the physical random access procedure


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Page 73

Transmit diversity Mode Application of Tx diversity modes on downlink physical channel

Physical channel type

Open loop mode

Closed loop mode

TSTD

STTD

Mode 1

Mode 2

–

applied

–

–

applied

–

–

–

S-CCPCH

–

applied

–

–

DPCH

–

applied

applied

applied

PICH

–

applied

–

–

HS-PDSCH

–

applied

applied

–

HS-SCCH

–

applied

–

–

AICH

–

applied

–

–

P-CCPCH SCH


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Page 74

Transmit Diversity-STTD Space time block coding based transmit antenna diversity(STTD） 4 consecutive bits b0, b1, b2, b3 using STTD coding

b0 b1 b2 b3

Antenna 1

b0 b1 b2 b3

Channel bits

-b 2 b 3 b 0 -b 1 Antenna 2

STTD encoded channel bits for antenna 1 and antenna 2.


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Page 75

Transmit Diversity-TSTD Time switching transmit diversity (TSTD) is used only on SCH channel.

Slot #0

Slot #1

Slot #14

Slot #2

ac p

(Tx OFF)

acp

ac p

i,0

(Tx OFF)

acsi,2

aci,14 s

Antenna 1

ac s

(Tx OFF)

acp

(Tx OFF)

(Tx OFF)

Antenna 2 (Tx OFF)

i,1

acs


(Tx OFF)

(Tx OFF)

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Page 76

Closed –Loop Mode


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Page 77

Transmit Diversity－Closed Loop Mode Closed loop mode transmit diversity Used in DPCH and PDSCH； Channel coding, interleaving and spreading are done as in nondiversity mode. The spread complex valued signal is fed to both TX antenna branches, and weighted with antenna specific weight factors w1 and w2. The weight factors are determined by the UE, and signalled to the UTRAN access point (=cell transceiver) using the D-bits of the FBI field of uplink DPCCH. The calculation of weight factor is the key point of closed loop Tx diversity.there are two modes with different calculation methods of weight factor： T 1、mode 1 uses phase adjustment；the dedicated pilot symbols of two antennas are different(orthogonal) T 2、mode 2 uses phase/amplitude adjustment； the dedicated pilot symbols of two antennas are the same. HUAWEI TECHNOLOGIES CO., LTD.

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Page 78

Thank You www.huawei.com

WCDMA Radio Interface Physical Layer.pdf

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